In a barbershop quartet, a tenor sings the melody, a countertenor sings above, and baritone and bass sing below.

Wine blends create harmonies in similar ways.

Wines blended from two or more grapes are among the world's best. They range from traditional ones with centuries-old formulas to freewheeling blends that mix almost anything, occasionally even white grapes among the reds.

At the traditional end, France's red Bordeaux, arguably the standard for all red wines, are blends of at least two of five grapes: cabernet sauvignon for structure and berry flavors; merlot for smoothness; cabernet franc for aromas of flowers and earth; malbec for inky violet hue; and petit verdot for spice.

In the old days, blending was done in hopes the strengths of one grape would cover shortcomings of another. If the late- ripening cabernet sauvignon didn't get fully mature, merlot would smooth it out with sweet fruit and soft tannins. And so on.

These scientific days, growers can make excellent unblended wines most years from most grape varieties. California's Echelon Vineyards 2010 Alexander Valley Cabernet Sauvignon is 100 percent from that grape.

Still, winemakers often blend in other grapes simply to make the best wine they can. Or maybe just for fun.

And since Bordeaux's red wines, with their five-grape recipe, are the world standard, a group of American vintners in 1988 formed the Meritage Association to make wines here to that formula.

Today, Meritagealliance .com lists 283 winery members in 22 states. Its goal is to create "an American expression of excellence for wines blended in the Bordeaux tradition."

Some of America's top wines are meritages. The Rodney Strong Vineyards 2009 "Symmetry" Red Meritage from Alexander Valley is made of cabernet sauvignon, malbec, merlot and cabernet franc.

Continuum Estate's 2009 red wine, made by some of Robert Mondavi's children, has cabernet sauvignon, cabernet franc, petit verdot and merlot.

Outside the Bordeaux- meritage formula, American winemakers are experimenting with audacious blends including dozens of grapes.

There are rules. In California a wine must have 75 percent of a grape variety to be called by that name. Still, it leaves room for tinkering.

One small problem: Many wine fans, even wine stewards, don't understand the meritage concept. So there's a lot of mislabeling in wine lists. To see what you're getting, you might have to ask to see the bottle's label.

Finally, if you want to be pedantic, meritage isn't pronounced meri-TAAGHE in the French way. It rhymes with "heritage."

Highly recommended:

• 2009 Rodney Strong "Symmetry" Meritage Red Wine, Alexander Valley (79 percent cabernet sauvignon, 14 percent malbec, 6 percent merlot, 1 percent cabernet franc): sweet blackberry and spice aromas, flavors of blackberries and bittersweet chocolate, very smooth, opulent; $55.

• 2009 Mettler Family Vineyards Estate Grown "Old Vine" Zinfandel, Lodi (78 percent zinfandel, 12 percent petite sirah, 8 percent cabernet sauvignon, 2 percent cabernet franc): rich aromas and flavors of red plums, sweet chocolate and spice; $20.

Recommended:

• 2010 Echelon Cabernet Sauvignon, Alexander Valley (100 percent cabernet sauvignon): aroma and flavor of black cherries and black coffee, smooth and rich; $18.

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